Solid-state image-capturing device and production method thereof, and electronic appliance

ABSTRACT

A high degree of phase difference detection accuracy can be obtained using a phase difference pixel ( 2 B) with a simpler configuration. A solid-state image-capturing device includes a pixel array unit in which a plurality of pixels including a phase difference pixel ( 2 B) which is a pixel for focal point detection and an image-capturing pixel ( 2 A) which is a pixel for image generation are arranged in a two-dimensional array. In this case, a predetermined layer ( 50 ) between a light shielding layer ( 47 ) and a micro lens ( 52 ) formed in the image-capturing pixel has a higher refraction index than a refraction index of the predetermined layer ( 51 ) formed in the phase difference pixel. The technique of the present disclosure can be applied to, for example, a back-illuminated-type solid-state image-capturing device and the like.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. 371 andclaims the benefit of PCT Application No. PCT/JP2014/003401 having aninternational filing date of Jun. 25, 2014, which designated the UnitedStates, which PCT application claimed the benefit of Japanese PatentApplication No. 2013-139832 filed Jul. 3, 2013, the disclosures of whichare incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a solid-state image-capturing device,a production method thereof, and an electronic appliance, and moreparticularly relates to a solid-state image-capturing device, aproduction method thereof, and an electronic appliance capable ofobtaining a high degree of phase difference detection accuracy using aphase difference pixel with a simpler configuration.

BACKGROUND ART

There is a solid-state image-capturing device in which a pixel arrayunit having multiple pixels arranged in an array form in atwo-dimensional manner includes not only ordinary pixels for imagegeneration (hereinafter referred to as image-capturing pixels) but alsophase difference pixels for focal point detection.

In order to obtain a high degree of phase difference detection accuracywith the phase difference pixels, the sensitivity needs to be highlydependent on the angle so that the phase difference pixels receive onlythe incidence light of a desired angle and generates an associatedoutput. In order to make the phase difference pixels of whichsensitivities are highly dependent on the angle, it is most effective toincrease the film thickness of an inter-layer film of a phase differencepixel (makes a thicker film).

However, when an inter-layer film is simply made thicker, theimage-capturing pixels are also made into thicker films, and therefore,the image-capturing pixels would have a poor diagonal incidenceproperty. More specifically, although it is desirable for theimage-capturing pixel to receive light from a diagonal direction ofwhich incidence angle is large, when the thickness of the film isincreased, the light from diagonal direction may not be received and thesensitivity is reduced.

Therefore, a solid-state image-capturing device has been suggested toimprove the detection accuracy of a phase difference pixel by employinga structure of the phase difference pixel which is different from thestructure of the image-capturing pixel. For example, PTL 1 discloses atechnique for making a structure of the phase difference pixel that isdifferent from the structure of the image-capturing pixel by forming anin-layer lens in the phase difference pixel and embedding a highrefraction index layer under the in-layer lens.

On the other hand, PTL 2 discloses an idea for changing the structure ofthe image-capturing pixel. More specifically, an inter-layer lens and alight guide are provided for the image-capturing pixel, so that, whilethe degradation of the characteristics of the image-capturing pixel issuppressed, the phase difference pixel is optimized, whereby thedetection accuracy of the phase difference pixel is improved.

In order to obtain a high degree of phase difference detection accuracyusing a phase difference pixel, a light shielding layer forpupil-splitting serves an important role. Therefore, PTL 3 discloses asolid-state image-capturing device that helps a light shielding layer bymaking the aperture width of a wiring layer of the uppermost layer ofthe phase difference pixel smaller than the aperture width of theimage-capturing pixel.

CITATION LIST Patent Literature

PTL 1: JP 2012-151367 A

PTL 2: JP 2008-71972 A

PTL 3: JP 2012-173492 A

SUMMARY OF INVENTION Technical Problem

However, in the technique disclosed in PTL 1, the wave front is sharplybent, and this may increase the reflection loss at the light receptionunit. In the technique disclosed in PTL 2, the image-capturing pixel isprovided with the inter-layer lens and the light guide, and this maygreatly increase the number of steps of production. Likewise, when thetechnique disclosed in PTL 3 is realized, at least wirings for twolayers are necessary, and therefore, in particular, when this is appliedto a back-illuminated solid-state image-capturing device, this maygreatly increase the number of steps of production.

The present disclosure is made in view of such circumstances, and thepresent disclosure obtains a high degree of phase difference detectionaccuracy using a phase difference pixel with a simpler configuration.

Solution to Problem

A solid-state image-capturing device according to a first aspect of thepresent disclosure includes a pixel array unit having a plurality ofpixels arranged in a two-dimensional array, the plurality of pixelsincluding a phase difference pixel and an image-capturing pixel, and alayer between a light shielding layer and a micro lens formed in theimage-capturing pixel, wherein the layer between the light shieldinglayer and the micro lens formed in the image-capturing pixel has ahigher refraction index than a refraction index of a layer formed in thephase difference pixel.

In a production method for producing a solid-state image-capturingdevice having a plurality of pixels including a phase difference pixeland an image-capturing pixel according to a second aspect of the presentdisclosure, wherein the production method includes forming a lightshielding layer in at least the image-capturing pixel, forming a firstlayer in the image-capturing pixel with a material having a higherrefraction index than a refraction index of a first in the phasedifference pixel, and forming a micro lens above the first layer.

An electronic appliance according to a third aspect of the presentdisclosure includes a solid-state image-capturing device including apixel array unit having a plurality of pixels including a phasedifference pixel and an image-capturing pixel arranged in atwo-dimensional array, and a layer between a light shielding layer and amicro lens formed in the image-capturing pixel, wherein the layerbetween the light shielding layer and the micro lens formed in theimage-capturing pixel has a higher refraction index than a refractionindex of a layer formed in the phase difference pixel.

In the first to the third aspects of the present disclosure, in thepixel array unit in which the plurality of pixels including the phasedifference pixel which is the pixel for focal point detection and theimage-capturing pixel which is the pixel for image generation arearranged a two-dimensional array, the layer between the light shieldinglayer and the micro lens formed in the image-capturing pixel has ahigher refraction index than the refraction index of the layer formed inthe phase difference pixel.

An electronic appliance according to a fourth aspect of the presentdisclosure includes a solid-state image-capturing device including apixel array unit having a plurality of pixels including a phasedifference pixel and an image-capturing pixel arranged in atwo-dimensional array, wherein an aperture shape of a light shieldinglayer of the phase difference pixel is a shape for shielding light inareas in proximity to the four corners of a rectangular pixel area.

In the fourth aspect of the present disclosure, in the pixel array unitin which the plurality of pixels including the phase difference pixelwhich is the pixel for focal point detection and the image-capturingpixel which is the pixel for image generation are arranged in atwo-dimensional array, the aperture shape of the light shielding layerof the phase difference pixel is the shape for shielding light in areasin proximity to the four corners of the pixel area.

The solid-state image-capturing device and the electronic appliance maybe independent devices, or may be modules incorporated into otherdevices.

Advantageous Effects of Invention

According to the first to the fourth aspects of the present disclosure,a high degree of phase difference detection accuracy can be obtainedusing a phase difference pixel with a simpler configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a figure illustrating a schematic configuration of asolid-state image-capturing device according to an embodiment of thepresent disclosure.

FIG. 2 is a cross sectional configuration diagram of pixels according toa first embodiment.

FIG. 3 is a figure for explaining diagonal incidence characteristic of apixel structure of the first embodiment.

FIGS. 4A to 4F are figures for explaining a production method of pixelsaccording to the first embodiment.

FIG. 5 is a cross sectional configuration diagram of pixels according toa second embodiment.

FIG. 6 is a cross sectional configuration diagram of pixels according toa third embodiment.

FIGS. 7A to 7F are figures for explaining a production method of pixelsaccording to the third embodiment.

FIG. 8 is a cross sectional configuration diagram of pixels according toa fourth embodiment.

FIGS. 9A to 9E are figures for explaining a production method of pixelsaccording to the fourth embodiment.

FIG. 10 is a cross sectional configuration diagram of pixels accordingto a fifth embodiment.

FIGS. 11A to 11D are top views illustrating light shielding layers for aphase difference pixel.

FIGS. 12A and 12B are figures for explaining aperture shapes of lightshielding layers for a phase difference pixel.

FIG. 13 is a figure for explaining an effect of a pixel structureaccording to an embodiment of the present disclosure.

FIG. 14 is a figure illustrating modifications of aperture widths ofphase difference pixels.

FIG. 15 is a figure illustrating modifications of aperture directions ofphase difference pixels.

FIGS. 16A to 16C are figures illustrating modifications of apertureshapes of phase difference pixels.

FIG. 17 is a cross sectional configuration diagram illustrating pixelsin a case of a front-illuminated solid-state image-capturing device.

FIG. 18 is a figure for explaining diagonal incidence characteristic ina case of a front-illuminated solid-state image-capturing device.

FIG. 19 is a block diagram illustrating an example of configuration ofan image-capturing device as an electronic appliance according to anembodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Modes for carrying out the present disclosure (hereinafter referred toas embodiments) will be explained. It should be noted that theexplanation will be made in the following order.

1. Example of schematic configuration of solid-state image-capturingdevice according to an embodiment of the present disclosure

2. First embodiment of pixels (embodiment in which high refraction indexlayer and low refraction index layer are disposed between color filterlayer and micro lens)

3. Second embodiment of pixels (embodiment in which planarization filmis disposed between high refraction index layer, low refraction indexlayer, and micro lens)

4. Third embodiment of pixels (embodiment in which high refraction indexlayer and low refraction index layer are disposed between color filterlayer and planarization film)

5. Fourth embodiment of pixels (embodiment in which color filter layeris high refraction index layer)

6. Fifth embodiment of pixels (embodiment in which transparent colorfilter layer is low refraction index layer)

7. Aperture shape of light shielding layer

8. Modification of aperture width of light shielding layer

9. Modification of aperture direction of light shielding layer

10. Modification of aperture shape of light shielding layer

11. Example of application to front-illuminated type

12. Example of configuration of electronic appliance according to anembodiment of the present disclosure

<1. Example of Schematic Configuration of Solid-State Image-CapturingDevice>

FIG. 1 illustrates a schematic configuration of a solid-stateimage-capturing device according to an embodiment of the presentdisclosure.

A solid-state image-capturing device 1 of FIG. 1 includes a pixel arrayunit 3, in which pixels 2 are arranged in an array form in atwo-dimensional manner, and a peripheral circuit unit therearound, whichare provided on a semiconductor substrate 12 using silicon (Si) assemiconductor, for example. The peripheral circuit unit includes, forexample, a vertical drive circuit 4, a column signal processing circuit5, a horizontal drive circuit 6, an output circuit 7, a control circuit8, and the like.

In the pixel array unit 3, the pixels 2 arranged in an array form in atwo-dimensional manner include image-capturing pixels 2A for generatinga signal for image generation and phase difference pixels 2B forgenerating a signal for focal point detection. The difference betweenthe image-capturing pixel 2A and the phase difference pixel 2B will beexplained later.

The pixel 2 includes a photodiode serving as a photoelectric conversionelement and multiple pixel transistors (so-called MOS transistors). Themultiple pixel transistors include four MOS transistors, for example, atransfer transistor, a selection transistor, a reset transistor, and anamplification transistor.

The pixels 2 may have a shared pixel structure. This pixel-sharedstructure includes multiple photodiodes, multiple transfer transistors,a shared floating diffusion (floating diffusion area), and each of othershared pixel transistors. More specifically, in the shared pixels, thephotodiodes and the transfer transistors having multiple unit pixels areconfigured to share each of other pixel transistors.

The control circuit 8 receives, for example, data commanding anoperation mode and an input clock, and outputs data such as internalinformation about the solid-state image-capturing device 1. Morespecifically, the control circuit 8 generates a clock signal and acontrol signal serving as a reference of operation of, for example, thevertical drive circuit 4, the column signal processing circuit 5, andthe horizontal drive circuit 6, on the basis of the verticalsynchronization signal, the horizontal synchronization signal, and themaster clock. Then, the control circuit 8 outputs the clock signal andthe control signal thus generated to, for example, the vertical drivecircuit 4, the column signal processing circuit 5, and the horizontaldrive circuit 6.

The vertical drive circuit 4 includes, for example, shift registers, andselects a pixel drive wire 10, and provides a pulse for driving thepixels 2 to the selected pixel drive wire 10, thus driving the pixels 2in units of rows. More specifically, the vertical drive circuit 4selects and scans the pixels 2 of the pixel array unit 3 in units ofrows in the vertical direction in order, and provides the pixel signalgenerated based on the signal electrical charge generated in accordancewith the quantity of light reception by the photoelectric conversionunit of each pixel 2 to the column signal processing circuit 5 via avertical signal line 9.

The column signal processing circuit 5 is provided for each column ofthe pixels 2, and performs signal processing such as noise reduction foreach pixel column on the signals which are output from the pixels 2 forone row. For example, the column signal processing circuit 5 performssignal processing such as CDS (Correlated Double Sampling) and ADconversion for removing fixed pattern noises unique to the pixels.

The horizontal drive circuit 6 includes, for example, shift registers,and outputs horizontal scanning pulses in order, thereby selecting eachof the column signal processing circuit 5 in order, and outputting thepixel signal from each of the column signal processing circuits 5 to ahorizontal signal line 11.

The output circuit 7 performs signal processing on the signals providedin order via the horizontal signal line 11 from each of the columnsignal processing circuits 5 and outputs the signals. The output circuit7 may, for example, only buffer the signals, or may perform variouskinds of digital signal processing such as black level adjustment,column variation correction, and the like. An input/output terminal 13exchanges signals to/from the outside.

The solid-state image-capturing device 1 configured as described aboveis a CMOS image sensor having a column AD method in which the columnsignal processing circuit 5 performing the CDS processing and the ADconversion processing are provided for each pixel column.

The solid-state image-capturing device 1 is a back-illuminated MOSsolid-state image-capturing device which receives light from the backsurface side opposite to the front surface side of the semiconductorsubstrate 12 on which the pixel transistors are formed.

<2. First Embodiment of Pixels>

<Cross Sectional Configuration View of Pixels>

FIG. 2 is a cross sectional configuration diagram of pixels 2 accordingto the first embodiment. FIG. 2 illustrates a cross sectionalconfiguration of an image-capturing pixel 2A and a phase differencepixel 2B which are adjacent to each other in the pixel array unit 3.

The structure of the image-capturing pixel 2A and the phase differencepixel 2B will be explained with reference to FIG. 2.

In the solid-state image-capturing device 1, for example, asemiconductor area 42 of an N-type (second conductivity-type) is formedin a semiconductor area 41 of a P-type (first conductivity-type) of thesemiconductor substrate 12 for each pixel 2, so that the photodiode PDis formed in units of pixels. The P-type semiconductor area 41 facingboth of the front and back surfaces of the semiconductor substrate 12also serves as a positive hole electrical charge accumulation area forsuppressing a dark current.

At the front surface side of the semiconductor substrate 12 (the lowerside in the drawing), a multi-layer wire layer 45 is formed, whichincludes multiple pixel transistors Tr for, for example, readingelectrical charge accumulated in the photodiode PD, multiple wire layers43, and a layer insulating film 44.

At the interface of the back surface side of the semiconductor substrate12 (the upper side in the drawing), a reflection preventing film(insulating layer) 46 is formed, which includes multiple layers of whichrefraction indexes are different such as two layer films including ahafnium oxide (HfO2) film and a silicon oxide film.

At a portion of the upper side of the reflection preventing film 46, alight shielding layer 47 is formed. More specifically, in theimage-capturing pixel 2A, the light shielding layer 47 is formed only atthe pixel borders on the reflection preventing film 46 so that the lightis incident upon the entire surface of the photodiode PD. On the otherhand, in the phase difference pixel 2B, the light shielding layer 47 isformed not only at the pixel borders but also on the half at one side ofthe light reception surface of the photodiode PD (the half portion atthe left side in FIG. 2) so as to shield light.

The phase difference pixel 2B includes two types, for example, a type Ain which the half portion at the left side of the light receptionsurface of the photodiode PD is open and type B in which the halfportion at the right side of the light reception surface of thephotodiode PD is open, and these two types make a pair and are arrangedat a predetermined position of the pixel array unit 3. There isdifference in the image between the pixel signal from the type A and thepixel signal from the type B due to the difference in the position wherethe aperture portion is formed. The amount of defocus is calculated bycalculating the amount of phase difference from the deviation of theimages, and the image-capturing lens is adjusted (moved), so thatauto-focus can be achieved.

The light shielding layer 47 may be a material that shields light, butis desirably a material that has a high degree of light shieldingproperty, and that can be processed accurately in fine processingtechnique such as etching. The light shielding layer 47 can be formedwith a metal film such as tungsten (W), aluminum (Al), copper (Cu),titanium (Ti), molybdenum (Mo), and nickel (Ni).

On the reflection preventing film 46 including the light shielding layer47, a planarization film 48. The planarization film 48 is formed throughrotation/application of organic material such as resin. Alternatively,the planarization film 48 may also be formed by depositing an inorganicfilm such as SiO2 and planarizing the film by CMP (Chemical MechanicalPolishing).

On the planarization film 48, a color filter layer 49 is formed for eachpixel. The color filter layer 49 is formed by rotating and applyingphotosensitive resin including coloring matter such as pigments anddyes. In the arrangement of the color filter layer 49, colors of R(red), G (green), and B (blue) are arranged in, for example, Bayerarrangement, but may be arranged in other arrangement method. In theexample of FIG. 2, a G (green) color filter layer 49 is formed in theimage-capturing pixel 2A at the left side, and a B (blue) color filterlayer 49 is formed in the phase difference pixel 2B at the right side.It should be noted that the phase difference pixel 2B is not limited tothe B color filter layer 49.

At the upper side of the color filter layer 49, layers are formed ofwhich refraction indexes are different between the image-capturing pixel2A and the phase difference pixel 2B.

More specifically, at the upper side of the color filter layer 49 of theimage-capturing pixel 2A, a high refraction index layer 50 having arefraction index n_(a) is formed. At the upper side of the color filterlayer 49 of the phase difference pixel 2B, a low refraction index layer51 having a refraction index n_(b) is formed. In this case, thedifference of the refraction index between the high refraction indexlayer 50 and the refraction index of the low refraction index layer 51is equal to or more than 0.2(n _(a) −n _(a)≥0.2).

The high refraction index layer 50 and the low refraction index layer 51are formed to have the same thickness, that is, about

1 μm

so that the phase difference pixel 2B can have a thickness to be able tohave a sufficient level of phase difference detection accuracy.

The high refraction index layer 50 is formed with an inorganic film suchas nitride film (SiN), oxynitride (SiON), silicon carbide (SiC), and thelike. On the other hand, the low refraction index layer 51 is formedwith an oxide film (SiO2), and a resin material such as styrene resin,acrylic resin, styrene-acrylic copolymerization resin, or siloxaneresin.

Above the color filter layer 49, a micro lens (on-chip lens) 52 isformed for each pixel. The micro lens 52 is made of a material havingalmost the same refraction index as that of the low refraction indexlayer 51. The micro lens 52 is formed with a resin material such asstyrene resin, acrylic resin, styrene-acrylic copolymerization resin, orsiloxane resin.

The image-capturing pixel 2A and the phase difference pixel 2B of thepixel array unit 3 of the solid-state image-capturing device 1 areconfigured as described above.

<Diagonal Incidence Characteristic of Pixels>

FIG. 3 is a figure illustrating the state of propagation of diagonalincidence light in order to explain diagonal incidence characteristic ofthe pixel structure according to the first embodiment.

The structure of a generally-available back-illuminated-type solid-stateimage-capturing device corresponds to a structure obtained by removingthe high refraction index layer 50 and the low refraction index layer 51from the structure of the first embodiment shown in FIG. 2. In thiscase, the distance from the micro lens 52 to the light shielding layer47 is short, and therefore, the sensitivities are not sufficientlydependent on the angle, and the phase difference detection accuracy islow.

In the structure according to the present embodiment, the low refractionindex layer 51 is formed on the color filter layer 49 for the phasedifference pixel 2B, so that the sensitivity is highly dependent on theangle. More specifically, the low refraction index layer 51 is made asthe thick film so that diagonal incidence light other than a desiredangle is out of the aperture portion of the light shielding layer 47,and this increases the change of output with respect to the amount ofdefocus, and accordingly the phase difference detection accuracy isimproved.

In contrast, for the image-capturing pixel 2A, the low refraction indexlayer 51 is not formed. Instead, the high refraction index layer 50 ofwhich refraction index is different from the low refraction index layer51 by 0.2 or more is formed on the color filter layer 49. Therefore, theimage-capturing pixel 2A has the same device height as the phasedifference pixel 2B, but due to the refraction effect of the highrefraction index layer 50, the dependency on the angel can be reduced.Therefore, according to the solid-state image-capturing device 1employing the pixel structure of the first embodiment, while a highdegree of phase difference detection accuracy is realized in the phasedifference pixel 2B, the degradation of the characteristic of theimage-capturing pixel 2A can be reduced to a minimum.

<Production Method of Pixels According to First Embodiment>

Subsequently, a production method of pixels 2 according to the firstembodiment explained above will be explained with reference to FIGS. 4Ato 4F.

It should be noted that the production steps of the pixel 2 according tothe first embodiment until the color filter layer 49 is formed on theplanarization film 48 are the same as a conventional production methodof a back-illuminated-type solid-state image-capturing device, and inFIGS. 4A to 4F, the semiconductor substrate 12 on which the photodiodePD is formed and the multi-layer wire layer 45 on the front surface sidethereof are simplified or omitted from the drawing.

First, as shown in FIG. 4A, a reflection preventing film 46, a lightshielding layer 47, a planarization film 48, and a color filter layer 49are formed in order on the back surface side of the semiconductorsubstrate 12. The production method up to this point is the same as theconventional production method of the back-illuminated-type solid-stateimage-capturing device.

Subsequently, as shown in FIG. 4B, the low refraction index layer 51 isformed to be thicker (deposited) on the color filter layer 49 by, forexample, increasing the deposition time of the CVD method.

Subsequently, as shown in FIG. 4C, a resist 71 is patterned and etchedonly in the area of the phase difference pixel 2B of the pixel arrayunit 3, so that, as shown in FIG. 4D, the low refraction index layer 51in the area of the image-capturing pixel 2A is removed.

Then, as shown in FIG. 4E, the high refraction index layer 50 is formedto be thicker (deposited) in the area of the image-capturing pixel 2A,where the low refraction index layer 51 is removed, by, for example, theCVD method.

Finally, as shown in FIG. 4F, the micro lens 52 is formed with a resinmaterial having almost the same refraction index as that of the lowrefraction index layer 51. The micro lens 52 can be formed by performingpattern processing on a photosensitive resin material by, for example,lithography technique and thereafter changing it into a lens shape byreflow processing.

3. Second Embodiment of Pixels>

<Cross Sectional Configuration View of Pixels>

FIG. 5 is a cross sectional configuration diagram according to thesecond embodiment of pixels 2. In FIG. 5, the portions corresponding tothe first embodiment as shown in FIG. 2 are also denoted with the samereference numerals, and explanation about these portions are omitted asnecessary.

The second embodiment in FIG. 5 is different from the first embodimentin FIG. 2 in that a planarization film 81 is formed between the highrefraction index layer 50 and the low refraction index layer 51 and themicro lens 52.

The planarization film 81 is formed with, for example, acrylic resin.The planarization film 81 is formed by, for example, depositing aninorganic film such as SiO2 and planarizing the film by CMP. The filmthickness of the planarization film 81 may be, for example, about 300nm.

The planarization film 81 may be made of the same material as that ofthe low refraction index layer 51 or may be made of a material differentfrom that of the low refraction index layer 51, as long as it has aboutthe same refraction index as that of the low refraction index layer 51.Therefore, in the second embodiment, a layer of which refraction indexis less than that of the high refraction index layer 50 is formedbetween the high refraction index layer 50 and the low refraction indexlayer 51 and the micro lens 52.

In the second embodiment, the difference in the refraction index betweenthe low refraction index layer 51 and the high refraction index layer 50is configured to be equal to or more than 0.2. Therefore, in theimage-capturing pixel 2A, the angle dependency is reduced due to theeffect of refraction by the high refraction index layer 50, and in thephase difference pixel 2B, the angle dependency is enhanced by the lowrefraction index layer 51. Therefore, in the solid-state image-capturingdevice 1 that employs the pixel structure according to the secondembodiment, while a high degree of phase difference detection accuracyis realized in the phase difference pixel 2B, the degradation of thecharacteristic of the image-capturing pixel 2A can be reduced to aminimum.

The production method of pixels 2 according to the second embodimentwill be explained with reference to FIGS. 4A to 4F.

As shown in FIG. 4E, the pixel 2 according to the second embodiment isformed as follows: the high refraction index layer 50 and the lowrefraction index layer 51 are formed on the color filter layer 49 andthereafter the planarization film 81 is formed. The planarization film81 can be formed by applying, for example, acrylic resin material by aspin coat method and carrying out thermosetting treatment. Thereafter,the micro lens 52 is formed by resin material having almost the samerefraction index as that of the low refraction index layer 51.

<4. Third Embodiment of Pixels>

<Cross Sectional Configuration View of Pixels>

FIG. 6 is a cross sectional configuration diagram according to the thirdembodiment of pixels 2. In FIG. 6, the portions corresponding to thefirst embodiment as shown in FIG. 2 are denoted with the same referencenumerals, and explanation about these portions are omitted as necessary.

The third embodiment of FIG. 6 is different from the first embodiment ofFIG. 2 in that the layer of the high refraction index layer 50 and thelow refraction index layer 51 and the color filter layer 49 are oppositeto those of the first embodiment as shown in FIG. 2.

More specifically, in the third embodiment, the high refraction indexlayer 50 is formed in the area of the image-capturing pixel 2A at theupper side of the planarization film 48, and the low refraction indexlayer 51 is formed in the area of the phase difference pixel 2B at theupper side of the planarization film 48. Then, the color filter layer 49is formed at the upper side of, the high refraction index layer 50 andthe low refraction index layer 51.

In the third embodiment, the difference in the refraction index betweenthe low refraction index layer 51 and the high refraction index layer 50is configured to be equal to or more than 0.2. Therefore, in theimage-capturing pixel 2A, the angle dependency is reduced due to theeffect of refraction by the high refraction index layer 50, and in thephase difference pixel 2B, the angle dependency is enhanced by the lowrefraction index layer 51. Therefore, in the solid-state image-capturingdevice 1 that employs the pixel structure according to the thirdembodiment, while a high degree of phase difference detection accuracyis realized in the phase difference pixel 2B, the degradation of thecharacteristic of the image-capturing pixel 2A can be reduced to aminimum.

<Production Method of Pixels According to Third Embodiment>

A production method of pixels 2 according to the third embodimentexplained above will be explained with reference to FIGS. 7A to 7F.

FIGS. 7A to 7F are the same as FIGS. 4A to 4F in that the semiconductorsubstrate 12 and the multi-layer wire layer 45 on the front surface sidethereof are simplified or omitted from the drawing.

First as shown in FIG. 7A, a reflection preventing film 46, a lightshielding layer 47, and a planarization film 48 are formed in order onthe back surface side of the semiconductor substrate 12. The productionmethod up to this point is the same as the conventional productionmethod of the back-illuminated-type solid-state image-capturing device.

Subsequently, the low refraction index layer 51 is formed to be thicker(deposited) on the planarization film 48 by, for example, the CVDmethod. It should be noted that the planarization film 48 and the lowrefraction index layer 51 can be formed with the same material, and insuch case, the planarization film 48 and the low refraction index layer51 can be formed in the same process until the total film thickness ofthe planarization film 48 and the low refraction index layer 51 isattained.

Subsequently, as shown in FIG. 7C, a resist 71 is patterned and etchedjust like FIG. 4D explained above, the low refraction index layer 51 inthe area of the image-capturing pixel 2A is removed.

Then, as shown in FIG. 7D, the high refraction index layer 50 is formedto be thicker (deposited) in the area of the image-capturing pixel 2A,where the low refraction index layer 51 is removed by, for example, theCVD method.

Subsequently, as shown in FIG. 7E, at the upper side of the highrefraction index layer 50 and the low refraction index layer 51, thecolor filter layer 49 is formed by applying photosensitive resinincluding coloring matter such as pigments and dyes and performingpattern processing.

Finally, as shown in FIG. 7F, the micro lens 52 is formed with a resinmaterial having almost the same refraction index as that of the lowrefraction index layer 51.

<5. Fourth Embodiment of Pixels>

<Cross Sectional Configuration View of Pixels>

FIG. 8 is a cross sectional configuration diagram according to thefourth embodiment of pixels 2. In FIG. 8, the portions corresponding tothe first embodiment as shown in FIG. 2 are also denoted with the samereference numerals, and explanation about these portions are omitted asnecessary.

In the fourth embodiment of FIG. 8, the low refraction index layer 51 isformed at the upper side the planarization film 48 of theimage-capturing pixel 2A and the phase difference pixel 2B to have suchthickness that a sufficient level of phase difference detection accuracycan be obtained. The low refraction index layer 51 may be made of thesame material as that of the planarization film 48 below the lowrefraction index layer 51 or may be made of a material different fromthat of the low refraction index layer 51.

The color filter layer 49 is formed in the area of the image-capturingpixel 2A at the upper side of the low refraction index layer 51. Thecolor filter layer 49 is made of photosensitive resin including coloringmatter such as pigments and has almost the same refraction index as thatof the high refraction index layer 50.

On the other hand, the material of the micro lens 52 is embedded in thearea of the phase difference pixel 2B which is the same layer as thehigh refraction index layer 50, and is integrally formed with the microlens 52 formed at the uppermost portion of each pixel 2.

In the fourth embodiment, the color filter layer 49 has a highrefraction index (n_(a)) which is almost the same as that of the highrefraction index layer 50, and the micro lens 52 has a low refractionindex (n_(b)) which is almost the same as that of the low refractionindex layer 51, and therefore, the color filter layer 49 of theimage-capturing pixel 2A and the material layer of the micro lens 52having the same thickness are configured such that the difference in therefraction index is equal to or more than 0.2. Therefore, in theimage-capturing pixel 2A, the dependency upon the angle is reduced dueto the refraction effect of the color filter layer 49, and in the phasedifference pixel 2B, the dependency on the angel is enhanced by thematerial layer of the micro lens 52. Therefore, in the solid-stateimage-capturing device 1 that employs the pixel structure according tothe fourth embodiment, while a high degree of phase difference detectionaccuracy is realized in the phase difference pixel 2B, the degradationof the characteristic of the image-capturing pixel 2A can be reduced tothe minimum.

In the fourth embodiment, a sufficient level of dependency upon theangle can be obtained with a smaller amount of increase in the filmthickness as compared with the case where the color filter layer 49having the high refraction index is formed in the phase difference pixel2B, and therefore, the degradation of the characteristic of theimage-capturing pixel 2A can be suppressed. In addition, in the phasedifference pixel 2B, there is no absorption by the color filter layer49, and therefore the sensitivity increases. Therefore, in the phasedifference pixel 2B, a high degree of phase difference detectionaccuracy can be obtained.

<Production Method of Pixels According to Fourth Embodiment>

A production method of pixels 2 according to the fourth embodimentexplained above will be explained with reference to FIGS. 9A to 9E.

FIGS. 9A to 9E are the same as FIGS. 4A to 4F in that the semiconductorsubstrate 12 and the multi-layer wire layer 45 on the front surface sidethereof are simplified or omitted from the drawing.

First, as shown in FIG. 9A, a reflection preventing film 46, a lightshielding layer 47, and a planarization film 48 are formed in order onthe back surface side of the semiconductor substrate 12. The productionmethod up to this point is the same as the conventional productionmethod of the back-illuminated-type solid-state image-capturing device.

Subsequently, as shown in FIG. 9B, the low refraction index layer 51 isformed to be thicker (deposited) on the planarization film 48 by, forexample, the CVD method, until such a thickness is obtained such that asufficient level of phase difference detection accuracy can be obtained.

Subsequently, as shown in FIG. 9C, the color filter layer 49 can beformed by applying, for example, photosensitive resin including coloringmatter such as pigments and dyes to the entire surface of theplanarization film 48 by a coating method such as a spin coat method andcarrying out thermosetting treatment.

Then, as shown in FIG. 9D, the resist 71 is patterned and etched only inthe area of the image-capturing pixel 2A, so that the color filter layer49 in the area of the phase difference pixel 2B is removed.

Then, after the resist 71 is removed, the material of the micro lens 52is embedded as shown in FIG. 9E, and is integrally formed with the microlens 52 formed at the uppermost portion of each pixel 2.

<6. Fifth Embodiment of Pixels>

<Cross Sectional Configuration View of Pixels>

FIG. 10 is a cross sectional configuration diagram according to thefifth embodiment of pixels 2.

In the fourth embodiment as shown in FIG. 8, the material of the microlens 52 is embedded in the corresponding portion of the phase differencepixel 2B which is a counterpart of the color filter layer 49 formed inthe image-capturing pixel 2A. In the fifth embodiment, as shown in FIG.10, a transparent (white) color filter layer 49B using a material ofwhich refraction index is about the same as that of the low refractionindex layer 51 (that is, n_(b)) is formed in the corresponding portionof the phase difference pixel 2B. It should be noted that the lowrefraction index layer 51 itself may be embedded into the correspondingportion of the phase difference pixel 2B.

<7. Aperture Shape of Light Shielding Layer>

Subsequently, the aperture shape of the light shielding layer 47 of thephase difference pixel 2B of the solid-state image-capturing device 1will be explained.

FIGS. 11A and 11B are top views illustrating a conventional lightshielding layer. FIGS. 11C and 11D are top views illustrating the lightshielding layer 47 of the phase difference pixel 2B.

As shown in FIGS. 11A and 11B, the aperture shapes of a conventionallight shielding layer are rectangular shapes for pupil-splitting thelight reception surface of the photodiode PD into the half portion atthe left side and the half portion at the right side.

In contrast, the aperture shapes of the light shielding layer 47 of thephase difference pixel 2B of the solid-state image-capturing device 1are based on the conventional aperture shapes for pupil-splitting intothe half portion at the left side and the half portion at the rightside, but is further configured such that the areas in proximity to thefour corners of the rectangular pixel area are configured into ahexagonal shape for shielding light as shown in FIGS. 11C and 11D. Asdescribed above, when the areas in proximity to the four corners of therectangular pixel area are made into a narrower polygonal shape,unnecessary light that is incident from the flat portion (gap portion)of the micro lens 52 in proximity to the four corners of the pixel areacan be shielded.

FIGS. 12A and 12B are figures illustrating a light shielding layer forpupil-splitting the half portion at the right side and the lightshielding layer 47 of the phase difference pixel 2B overlaid with alight passage area 81.

In the light passage area 81 as shown in FIGS. 12A and 12B, areas 81 ain proximity to the four corners of the pixel area enclosed by brokenlines are areas of unnecessary light incident from the flat portion (gapportion) of the micro lens 52 in proximity to the four corners of therectangular pixel area.

As shown in FIG. 12B, the light shielding layer 47 is in the hexagonalshape in which the areas in proximity to the four corners of the pixelarea are narrowed, and therefore, the phase difference pixel 2B canshield unnecessary light in the areas 81 a. Therefore, the S/N ratio ofthe pixel signal is improved, and the angle dependency of the phasedifference pixel 2B can be improved, and therefore, a high degree ofphase difference detection accuracy can be realized. For example, theaperture shape of the light shielding layer 47 of the phase differencepixel is a shape in which areas in proximity to the four corners of arectangular pixel area are narrowed, such as in the shape of anirregular hexagon.

<Effects of Pixel Structure According to an Embodiment of the PresentDisclosure>

The effects of the pixel structure according to an embodiment of thepresent disclosure will be explained with reference to FIG. 13.

FIG. 13 is a figure illustrating incidence angle dependencycharacteristic illustrating relationship between the incidence angle andthe signal output when the light is incident thereupon, and illustratinga comparison between the pixel structure of the present disclosure and aconventional pixel structure.

In this case, the conventional pixel structure means a structure inwhich the low refraction index layer has a thicker film thickness ineach pixel including the image-capturing pixel, and the aperture shapeof the light shielding layer is a rectangular shape as shown in FIGS.11A and 11B in order to enhance the phase difference detection accuracyin the phase difference pixel for the conventional back-illuminated-typepixel structure. In other words, the conventional pixel structure is astructure in which no high refraction index layer 50 is provided, andonly the low refraction index layer 51 is thicker on all of the pixels,and the aperture shape of the light shielding layer is a rectangularshape as shown in FIGS. 11A and 11B.

In FIG. 13, the incidence angle dependency characteristics of the solidlines indicate the incidence angle dependency characteristics of theimage-capturing pixel 2A and the phase difference pixel 2B, and theincidence angle dependency characteristics of the broken lines indicatethe incidence angle dependency characteristics of the image-capturingpixel and the phase difference pixel of the conventional structure. Thephase difference pixels 2B includes two types shown therein, whichinclude the phase difference pixel 2B (right) that passes light throughthe half portion at the right side of FIG. 11D and the phase differencepixel 2B (left) that passes light through the half portion at the leftside of FIG. 11C. The conventional phase difference pixels also includesuch two types.

According to the incidence angle dependency characteristics as shown inFIG. 13, the image-capturing pixel 2A is provided with the highrefraction index layer 50, and therefore, as compared with theconventional pixel structure, the signal output at the diagonalincidence angle is increased, and the degradation of the diagonalincidence characteristic is reduced to a low level.

In the phase difference pixel 2B, the sensitivity is more greatlydependent on the angle as compared with the conventional case, due tothe increased film thickness of the low refraction index layer 51 andthe light shielding layer 47 in the hexagonal shape for shieldingunnecessary light incident from the flat portion (gap portion) of themicro lens 52. More specifically, as compared with the conventionalpixel structure, the output greatly changes in response to small changeof the incidence angel at around an incidence angle of zero degreeswhere the output of the phase difference pixel 2B (right) and the outputof the phase difference pixel 2B (left) are switched.

Therefore, according to the pixel structure of the present disclosure,while a high degree of phase difference detection accuracy is realizedin the phase difference pixel 2B, the degradation of the characteristicof the image-capturing pixel 2A can be reduced to the minimum.

<8. Modification of Aperture Width of Light Shielding Layer>

In each of the embodiments explained above, an example has beenexplained, in which, the aperture portion of the light shielding layer47 of the phase difference pixel 2B is pupil-split into the half portionat the right side and the half portion at the left side with the borderat the center of the optical axis (light reception area), a so-calledimage height of zero percent, as shown in FIGS. 11C and 11D.

However, as shown in FIG. 14, a pair of phase difference pixels 2Bhaving light shielding layers 47 of aperture portions which ispupil-split at the image height at the plus side (+ side) and a pair ofphase difference pixels 2B having light shielding layers 47 of apertureportions which is pupil-split at the image height at the minus side (−side) may be arranged at any given position of the pixel array unit 3.More specifically, the pixel array unit 3 may be arranged with multiplepairs of phase difference pixels 2B of which aperture widths of thelight shielding layers 47 (the widths in the pupil-split direction) aredifferent.

<9. Modification of Aperture Direction of Light Shielding Layer>

FIG. 14 is an example of pupil split in the left-right direction, andwhere the aperture direction of the aperture portion of the phasedifference pixel 2B is adopted as the left-right direction. However, theaperture direction of the aperture portion is not limited to theleft-right direction, and may be an upward/downward direction as shownin FIG. 15 or a diagonal direction (not shown).

Further, multiple phase difference pixels 2B of which aperturedirections of the light shielding layers 47 are different may exist in amixed manner in the pixel array unit 3, for example, phase differencepixels 2B of which aperture directions of the light shielding layers 47are the upward/downward direction and phase difference pixels 2B ofwhich aperture directions of the light shielding layers 47 are theleft-right direction exist in a mixed manner.

<10. Modification of Aperture Shape of Light Shielding Layer>

FIGS. 16A to 16C illustrate other examples of aperture shapes of thelight shielding layer 47 of the phase difference pixel 2B.

The aperture shape of the light shielding layer 47 of the phasedifference pixel 2B is not limited to the hexagonal shape as shown inFIGS. 11C and 11D as long as it is a shape in which the areas inproximity to the four corners of the rectangular pixel area arenarrowed. For example, the shapes as shown in FIGS. 16A to 16C can beemployed as the aperture shapes of the light shielding layer 47 of thephase difference pixel 2B.

FIG. 16A illustrates an example where the aperture shape of the lightshielding layer 47 of the phase difference pixel 2B is an octagonalshape which is a shape obtained by pupil-splitting a regular dodecagonalshape at a predetermined image height.

FIG. 16B illustrates an example where the aperture shape of the lightshielding layer 47 of the phase difference pixel 2B is a semicircularshape which is a shape obtained by pupil-splitting a circular shape at apredetermined image height.

FIG. 16C illustrates an example where the aperture shape of the lightshielding layer 47 of the phase difference pixel 2B is a triangularshape which is a shape obtained by pupil-splitting a rhombic shape at apredetermined image height.

<11. Example of Application to Front-Illuminated Type>

The pixel structure of the present disclosure is not limited to theback-illuminated-type. The pixel structure of the present disclosure canalso be applied to a front-illuminated-type solid-state image-capturingdevice.

FIG. 17 illustrates a cross sectional configuration of theimage-capturing pixel 2A and the phase difference pixel 2B in a casewhere the pixel structure of the present disclosure is applied to afront-illuminated-type solid-state image-capturing device.

In the solid-state image-capturing device 1, for example, asemiconductor area 142 of an N-type is formed in a semiconductor area141 of a P-type of a semiconductor substrate 112 for each pixel 2, sothat the photodiode PD is formed in units of pixels.

At the upper side of the semiconductor substrate 112, a multi-layer wirelayer 145 is formed, which includes a light shielding layer 147,multiple wire layers 143, and a layer insulating film 144.

At the upper side of the multi-layer wire layer 145, a high refractionindex layer 150 having a refraction index n_(a) is formed in the area ofthe image-capturing pixel 2A, and a low refraction index layer 151having a refraction index n_(b) is formed in the area of the phasedifference pixel 2B. In this case, the difference in the refractionindex between the high refraction index layer 150 and the low refractionindex layer 151 is equal to or more than 0.2(n _(a) −n _(a)≥0.2).

Then, a reflection preventing film 152, a passivation film 153 made ofnitride film (SiN), and a planarization film 154 are formed in order atthe upper side of the high refraction index layer 150 and the lowrefraction index layer 151.

Further, a color filter layer 155 and a micro lens 156 are formed on theplanarization film 154.

FIG. 18 is a figure illustrating the state of propagation of diagonalincidence light in the cross sectional configuration diagramillustrating the image-capturing pixel 2A and the phase difference pixel2B of front-illuminated-type.

In the front-illuminated-type solid-state image-capturing device, thehigh refraction index layer 150 is formed to be thicker in theimage-capturing pixel 2A, and the low refraction index layer 151 isformed to be thicker in the phase difference pixel 2B. The difference inthe refraction index between the high refraction index layer 150 of theimage-capturing pixel 2A and the low refraction index layer 151 of thephase difference pixel 2B is configured to be equal to or more than 0.2.Accordingly, in the image-capturing pixel 2A, the angle dependency isreduced due to the refraction effect of the high refraction index layer150, and in the phase difference pixel 2B, the angle dependency isenhanced due to the low refraction index layer 151. Therefore, accordingto the front-illuminated-type solid-state image-capturing deviceemploying the pixel structure of the present disclosure, while a highdegree of phase difference detection accuracy is realized in the phasedifference pixel 2B, the degradation of the characteristic of theimage-capturing pixel 2A can be reduced to the minimum.

In the example of FIGS. 17 and 18, the high refraction index layer 150and the low refraction index layer 151 are formed to be thicker betweenthe multi-layer wire layer 145 and the reflection preventing film 152,but the location (layer) where the high refraction index layer 150 andthe low refraction index layer 151 are arranged may be any locationbetween the multi-layer wire layer 145 and the micro lens 156 like theback-illuminated-type explained above.

In the example explained above, the solid-state image-capturing devicehas been explained in which the first conductivity-type is P-type, andthe second conductivity-type is N-type, and the electrical charge isadopted as the signal electrical charge. Alternatively, the technique ofthe present disclosure can also be applied to a solid-stateimage-capturing device in which positive hole is adopted as signalelectrical charge.

<12. Example of Configuration of Electronic Appliance According to anEmbodiment of the Present Disclosure>

Further, the technique of the present disclosure is not limited toapplication to a solid-state image-capturing device. More specifically,the technique of the present disclosure can be applied to electronicappliances in general using a solid-state image-capturing device for animage retrieving unit (photoelectric conversion unit) such as animage-capturing device such as a digital still camera and a videocamera, a portable terminal device having an image-capturing function, acopying machine using a solid-state image-capturing device for an imagereading unit. The solid-state image-capturing device may be a modeformed as one-chip, or may be a module-like mode having animage-capturing function including an image-capturing unit, a signalprocessing unit, or an optical system packaged collectively.

FIG. 19 is a block diagram illustrating an example of configuration ofan image-capturing device serving as an electronic appliance accordingto an embodiment of the present disclosure.

An image-capturing device 100 of FIG. 19 includes an optical unit 101made of a lens group, a solid-state image-capturing device(image-capturing device) 102 employing the structure of the solid-stateimage-capturing device 1 of FIG. 1, and a DSP (Digital Signal Processor)circuit 103 which is a camera signal processing circuit. Theimage-capturing device 100 includes a frame memory 104, a display unit105, a recording unit 106, an operation unit 107, and a power supplyunit 108. The DSP circuit 103, the frame memory 104, the display unit105, the recording unit 106, the operation unit 107, and the powersupply unit 108 are connected to each other via a bus line 109.

The optical unit 101 retrieves incidence light (image light) from asubject, and forms an image on an image-capturing surface of thesolid-state image-capturing device 102. The solid-state image-capturingdevice 102 converts the light quantity of the incidence light condensedon the image-capturing surface by the optical unit 101 into an electricsignal in units of pixels and outputs the electric signal as a pixelsignal. As the solid-state image-capturing device 102, in thesolid-state image-capturing device 1 of FIG. 1, that is, the phasedifference pixel, while a high degree of phase difference detectionaccuracy is realized, the degradation of the characteristic of theimage-capturing pixel can be reduced to the minimum.

The display unit 105 is made of, for example, a panel-type displaydevice such as a liquid crystal panel and an organic EL (ElectroLuminescence) panel and the like, and displays a motion picture or astill picture captured by the solid-state image-capturing device 102.The recording unit 106 records a motion picture or a still picturecaptured by the solid-state image-capturing device 102 to a recordingmedium such as a hard disk and a semiconductor memory.

The operation unit 107 transmits operation commands of various kinds offunctions of the image-capturing device 100 according to a user'soperation. The power supply unit 108 provides, as necessary, variouskinds of power supplies serving as operating power supplies for the DSPcircuit 103, the frame memory 104, the display unit 105, the recordingunit 106, and the operation unit 107 to these targets to which theelectric is to be supplied.

When the solid-state image-capturing device 1 explained above is used asthe solid-state image-capturing device 102, the degradation of thecharacteristic of the image-capturing pixel can be reduced to a minimumwhile a high degree of phase difference detection accuracy is realizedin the phase difference pixel. Therefore, the qualities of the capturedimages can be enhanced in the image-capturing device 100 such as a videocamera, a digital still camera, further, a camera module for a mobiledevice such as a cellular phone.

The technique of the present disclosure is not limited to application tothe solid-state image-capturing device for capturing an image bydetecting distribution of incidence visible light quantity. Thetechnique of the present disclosure can be applied to a solid-stateimage-capturing device for capturing, as an image, distribution of thequantity of incidence of infrared ray, X-ray, or particles, and asolid-state image-capturing device in general (physical quantitydistribution detection device) such as a finger print detection sensorand the like for capturing an image by detecting distribution of otherphysical quantities such as pressures and capacitances in the broadsense.

The embodiments of the present disclosure is not limited to theembodiments explained above, and can be changed in various mannerswithin the scope not deviating from the gist of the present disclosure.

It should be noted that the present disclosure can be configured asfollows.

(1)

A solid-state image-capturing device including a pixel array unit inwhich a plurality of pixels including a phase difference pixel which isa pixel for focal point detection and an image-capturing pixel which isa pixel for image generation are arranged in an array form in atwo-dimensional manner,

wherein a predetermined layer between a light shielding layer and amicro lens formed in the image-capturing pixel has a higher refractionindex than a refraction index of the predetermined layer formed in thephase difference pixel.

(2)

The solid-state image-capturing device according to the above (1),wherein a difference of the refraction index between the predeterminedlayer of the image-capturing pixel and the predetermined layer of thephase difference pixel is equal to or more than 0.2.

(3)

The solid-state image-capturing device according to the above (1) or(2), wherein the predetermined layer is provided between the micro lensand a color filter layer at an upper side of the light shielding layer.

(4)

The solid-state image-capturing device according to any one of the above(1) to (3), wherein a layer of which refraction index is less than thatof the predetermined layer of the image-capturing pixel is furtherprovided between the micro lens and the predetermined layer of thepixel.

(5)

The solid-state image-capturing device according to the above (1) or(2), wherein the predetermined layer is provided between the lightshielding layer and a color filter layer at a lower side of the microlens.

(6)

The solid-state image-capturing device according to the above (1) or(2), wherein the predetermined layer is a color filter layer.

(7)

The solid-state image-capturing device according to the above (6),wherein the predetermined layer of the phase difference pixel is atransparent color filter layer.

(8)

The solid-state image-capturing device according to the above (1) or(2), wherein the predetermined layer of the image-capturing pixel is acolor filter layer, and the predetermined layer of the phase differencepixel is made of a same material as the micro lens.

(9)

The solid-state image-capturing device according to the above (1) or(2), wherein the predetermined layer of the phase difference pixel ismade of a same material as a planarization film for planarizing an upperportion of the light shielding layer.

(10)

The solid-state image-capturing device according to any one of the above(1) to (9), wherein an aperture shape of the light shielding layer ofthe phase difference pixel is a shape in which areas in proximity to thefour corners of a rectangular pixel area are narrowed.

(11)

The solid-state image-capturing device according to the above (10),wherein the aperture shape of the light shielding layer of the phasedifference pixel is a polygonal shape.

(12)

The solid-state image-capturing device according to the above (10),wherein the aperture shape of the light shielding layer of the phasedifference pixel is a semicircular shape.

(13)

The solid-state image-capturing device according to any one of the above(1) to (12), wherein there are a plurality of phase difference pixels ofwhich aperture widths of the light shielding layers are different.

(14)

The solid-state image-capturing device according to any one of the above(1) to (13), wherein there are a plurality of phase difference pixels ofwhich aperture directions of the light shielding layers are different.

(15)

A production method for producing a solid-state image-capturing device,wherein when a plurality of pixels including a phase difference pixelwhich is a pixel for focal point detection and an image-capturing pixelwhich is a pixel for image generation are formed, a predetermined layerbetween a light shielding layer and a micro lens formed in theimage-capturing pixel is formed with a material having a higherrefraction index than a refraction index of the predetermined layerformed in the phase difference pixel.

(16)

An electronic appliance including a solid-state image-capturing deviceincluding a pixel array unit in which a plurality of pixels including aphase difference pixel which is a pixel for focal point detection and animage-capturing pixel which is a pixel for image generation are arrangedin an array form in a two-dimensional manner, wherein a predeterminedlayer between a light shielding layer and a micro lens formed in theimage-capturing pixel has a higher refraction index than a refractionindex of the predetermined layer formed in the phase difference pixel.

(17)

An electronic appliance including a solid-state image-capturing deviceincluding a pixel array unit in which a plurality of pixels including aphase difference pixel which is a pixel for focal point detection and animage-capturing pixel which is a pixel for image generation are arrangedin an array form in a two-dimensional manner, wherein an aperture shapeof the light shielding layer of the phase difference pixel is a shapefor shielding light in areas in proximity to the four corners of arectangular pixel area.

(18)

A solid-state image-capturing device including a pixel array unit havinga plurality of pixels arranged in a two-dimensional array, the pluralityof pixels including a phase difference pixel and an image-capturingpixel; and a layer between a light shielding layer and a micro lensformed in the image-capturing pixel, wherein the layer between the lightshielding layer and the micro lens formed in the image-capturing pixelhas a higher refraction index than a refraction index of a layer formedin the phase difference pixel.

(19)

The solid-state image-capturing device according to the above (18),wherein a difference between the refraction index of the layer betweenthe light shielding layer and the micro lens of the image-capturingpixel and the refraction index of the layer of the phase differencepixel is greater than or equal to 0.2.

(20)

The solid-state image-capturing device according to the above (18) or(19), wherein the phase difference pixel includes a light shieldinglayer and a micro lens, and wherein at least one of the layer betweenthe light shielding layer and the micro lens of the image-capturingpixel and the layer between the light shielding layer and the micro lensof the phase difference pixel is provided between the micro lens and acolor filter at an upper side of the light shielding layer.

(21)

The solid-state image-capturing device according to any one of the above(18) to (20), wherein a second layer having a refraction index less thanthe refraction index of the layer between the light shielding layer andthe micro lens of the image-capturing pixel is provided between themicro lens and the layer of the image-capturing pixel.

(22)

The solid-state image-capturing device according to the above (18) or(19), wherein the phase difference pixel includes a light shieldinglayer and a micro lens and wherein at least one of the layer between thelight shielding layer and the micro lens of the image-capturing pixeland the layer between the light shielding layer and the micro lens ofthe phase difference pixel is provided between the light shielding layerand a color filter layer at a lower side of the micro lens.

(23)

The solid-state image-capturing device according to the above (18) or(19), wherein at least one of the layer between the light shieldinglayer and the micro lens of the image-capturing pixel and the layerbetween the light shielding layer and the micro lens of the phasedifference pixel is a color filter layer.

(24)

The solid-state image-capturing device according to the above (23),wherein the layer between the light shielding layer and the micro lensof the phase difference pixel is a transparent color filter layer.

(25)

The solid-state image-capturing device according to the above (18) or(19), wherein the layer between the light shielding layer and the microlens of the image-capturing pixel is a color filter layer, and the layerbetween the light shielding layer and the micro lens of the phasedifference pixel is made of a same material as the micro lens.

(26)

The solid-state image-capturing device according to the above (18) or(19), wherein the layer between the light shielding layer and the microlens of the phase difference pixel is made of a same material as aplanarization film for planarizing an upper portion of the lightshielding layer.

(27)

The solid-state image-capturing device according to any one of the above(18) to (26), wherein light incident upon a light shielding layer of thephase difference pixel forms at least two corner areas, and wherein anaperture shape of the light shielding layer of the phase differencepixel is a shape having at least two edges inset from the at least twocorner areas.

(28)

The solid-state image-capturing device according to the above (27),wherein the aperture shape of the light shielding layer of the phasedifference pixel is a polygonal shape.

(29)

The solid-state image-capturing device according to any one of the above(18) to (26), wherein an aperture shape of a light shielding layer ofthe phase difference pixel is a semicircular shape.

(30)

The solid-state image-capturing device according to any one of the above(18) to (29), wherein the plurality of pixels include a plurality ofphase difference pixels having light shielding layers of differentaperture widths.

(31)

The solid-state image-capturing device according to any one of the above(18) to (30), wherein the plurality of pixels include a plurality ofphase difference pixels having light shielding layers of differentaperture directions.

(32)

The solid-state image-capturing device according to any one of the above(18) to (31), wherein the phase difference pixel is a pixel for focalpoint detection and the image-capturing pixel which is a pixel for imagegeneration.

(33)

The solid-state image-capturing device according to any one of the above(18) to (32), wherein the layer formed in the phase difference pixel isa layer formed between a light shielding layer and a micro lens of thephase difference pixel.

(34)

A production method for producing a solid-state image-capturing devicehaving a plurality of pixels including a phase difference pixel and animage-capturing pixel, the method including forming a light shieldinglayer in at least the image-capturing pixel; forming a first layer inthe image-capturing pixel with a material having a higher refractionindex than a refraction index of a first in the phase difference pixel;and forming a micro lens above the first layer.

(35)

An electronic appliance including a solid-state image-capturing deviceincluding a pixel array unit having a plurality of pixels including aphase difference pixel and an image-capturing pixel arranged in atwo-dimensional array; and a layer between a light shielding layer and amicro lens formed in the image-capturing pixel, wherein the layerbetween the light shielding layer and the micro lens formed in theimage-capturing pixel has a higher refraction index than a refractionindex of a layer formed in the phase difference pixel.

(36)

An electronic appliance including a solid-state image-capturing deviceincluding a pixel array unit having a plurality of pixels including aphase difference pixel and an image-capturing pixel arranged in atwo-dimensional array, wherein an aperture shape of a light shieldinglayer of the phase difference pixel is a shape for shielding light inareas in proximity to the four corners of a rectangular pixel area.

REFERENCE SIGNS LIST

-   -   1 solid-state image-capturing device    -   2A image-capturing pixel    -   2B phase difference pixel    -   3 pixel array unit    -   47 light shielding layer    -   48 planarization film    -   49 color filter layer    -   50 high refractive index layer    -   51 low refractive index layer    -   52 micro lens    -   81 planarization film    -   100 image-capturing device    -   102 solid-state image-capturing device

The invention claimed is:
 1. A solid-state image-capturing device,comprising: a pixel array unit having a plurality of pixels arranged ina two-dimensional array, the plurality of pixels including a first pixeland a second pixel; a first layer between a light shielding layer and amicro lens formed in the first pixel; and a second layer between thelight shielding layer and a micro lens formed in the second pixel,wherein the first layer is not between the light shielding layer and themicro lens formed in the second pixel, wherein the second layer is notbetween the light shielding layer and the micro lens formed in the firstpixel, and wherein the second layer between the light shielding layerand the micro lens formed in the second pixel has a higher refractionindex than a refraction index of the first layer formed in the firstpixel.
 2. The solid-state image-capturing device according to claim 1,wherein a difference between the refraction index of the second layerbetween the light shielding layer and the micro lens of the second pixeland the refraction index of the first layer of the first pixel isgreater than or equal to 0.2.
 3. The solid-state image-capturing deviceaccording to claim 1, wherein a planarization film having a refractionindex less than the refraction index of the second layer between thelight shielding layer and the micro lens of the second pixel is providedbetween the micro lens and the second layer of the second pixel.
 4. Thesolid-state image-capturing device according to claim 1, wherein atleast one of the second layer between the light shielding layer and themicro lens of the second pixel and the first layer between the lightshielding layer and the micro lens of the first pixel is providedbetween the light shielding layer and a color filter layer at a lowerside of the micro lens.
 5. The solid-state image-capturing deviceaccording to claim 1, wherein the first layer between the lightshielding layer and the micro lens of the first pixel is made of a samematerial as a planarization film for planarizing an upper portion of thelight shielding layer.
 6. The solid-state image-capturing deviceaccording to claim 1, wherein light incident upon the light shieldinglayer of the first pixel forms at least two corner areas, and wherein anaperture shape of the light shielding layer of the first pixel is ashape having at least two edges inset from the at least two cornerareas.
 7. The solid-state image-capturing device according to claim 6,wherein the aperture shape of the light shielding layer of the firstpixel is a polygonal shape.
 8. The solid-state image-capturing deviceaccording to claim 1, wherein an aperture shape of the light shieldinglayer of the first pixel is a semicircular shape.
 9. The solid-stateimage-capturing device according to claim 1, wherein the plurality ofpixels include a plurality of first pixels, and wherein the first pixelsare phase difference pixels having light shielding layers forming adifferent aperture than at least an aperture width of the second pixel.10. The solid-state image-capturing device according to claim 1, whereinthe plurality of pixels include a plurality of first pixels, and whereinthe first pixels are phase difference pixels having light shieldinglayers of different aperture directions.
 11. The solid-stateimage-capturing device according to claim 1, wherein the first pixel isa pixel for focal point detection and the second pixel is a pixel forimage generation.
 12. A production method for producing a solid-stateimage-capturing device having a plurality of pixels including a firstpixel and a second pixel, the method comprising: forming a lightshielding layer in at least the first pixel; forming a first layer inthe first pixel at a first distance from the light shielding layer in adirection perpendicular to a back surface of a substrate, wherein thefirst layer is between the light shielding layer and a micro lens formedin the first pixel; forming a second layer in the second pixel at thefirst distance from the light shielding layer in the directionperpendicular to the back surface of the substrate, wherein the secondlayer is between the light shielding layer and a micro lens formed inthe second pixel, wherein the first layer is not between the lightshielding layer and the micro lens formed in the second pixel, whereinthe second layer is not between the light shielding layer and the microlens formed in the first pixel, wherein a material of the second layerhas a higher refraction index than a refraction index of a material ofthe first layer in the first pixel.
 13. An electronic appliancecomprising a solid-state image-capturing device including a pixel arrayunit having a plurality of pixels including a first pixel and a secondpixel arranged in a two-dimensional array; a first layer between a lightshielding layer and a micro lens formed in the first pixel; and a secondlayer between the light shielding layer and a micro lens formed in thesecond pixel, wherein the first layer is not between the light shieldinglayer and the micro lens formed in the second pixel, wherein the secondlayer is not between the light shielding layer and the micro lens formedin the first pixel, wherein the second layer between the light shieldinglayer and the micro lens formed in the second pixel has a higherrefraction index than a refraction index of the first layer formedbetween the light shielding layer and the micro lens formed in the firstpixel, and wherein the second layer between the light shielding layerand the micro lens formed in the second pixel is horizontally adjacentto the first layer formed in the first pixel.
 14. An electronicappliance comprising a solid-state image-capturing device including apixel array unit having a plurality of first pixels and a plurality ofsecond pixels arranged in a two-dimensional array, wherein the firstpixels include a low refraction index layer formed on a first one of alight shielding layer and a color filter layer, wherein the lowrefraction index layer is between the light shielding layer and a microlens formed in the first pixels, wherein the second pixels include ahigh refraction index layer formed on the first one of the lightshielding layer and the color filter layer, wherein the high refractionindex layer is between the light shielding layer and a micro lens formedin the second pixels, wherein the low refraction index layer is notbetween the light shielding layer and the micro lens formed in thesecond pixels, wherein the high refraction index layer is not betweenthe light shielding layer and the micro lens formed in the first pixels,and wherein an aperture shape of the light shielding layer of the firstpixels is a shape for shielding light in areas in proximity to the fourcorners of a rectangular pixel area.